ghost crater

A ghost crater is an impact crater that has been largely
buried under deposits of other material, such as a lava flow or ejecta from later impacts. All that may be visible is the circular outline of parts
of the crater rim and perhaps the peak of a central mountain. In other cases,
the original crater may have been completely submerged but later subsidence
has formed wrinkle ridges, which trace out the old position of the rim.